What is Addictive in Internet?
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14 The Open Addiction Journal, 2012, 5, (Suppl 1: M2) 14-19
Open Access
What is Addictive in Internet?
Gabriel Thorens*, Alexandre Wullschleger, Riaz Khan, Sophia Achab and Daniele Fabio Zullino
Division of Addictology, University Hospitals of Geneva, Switzerland
Abstract: Focusing on World of Warcraft (WoW), the most popular massive multiplayer online role playing game
(MMORPG), the present article stresses, that, similarly to addictive drugs, certain features of Internet applications may act
on the mesolimbic dopaminergic system, and thus become addictive.
The distinction is made between addictive products (e.g. nicotine, specific stimuli), first order vectors (e.g. tobacco, WoW
software) and second order vectors (e.g. cigarettes, internet technology).
Stimuli presented by Internet contents are described which have been reported in other contexts to induce addiction
related neurobiological activities, i.e. stimuli with reference to sexuality, social acceptance, fairness, cooperative social
interactions, social hierarchies, and humor.
The mode of presentation of these stimuli represents another important issue. The development of WoW can be described
as largely based on operant conditioning aspects, sequencing continuous and intermittent reinforcement, fixed- and
variable-ratio schedules, purposely to initiate and maintain repetitive behavior.
Regarding their addictive potential, the properties of the Internet technology can be discussed regarding two aspects: (a)
accessibility/facility of use, and (b) rapidity of action. The addictive properties of WoW have probably been facilitated by
the last technological developments, rendering the game more accessible, and permitting very strong time correlations
between potentially addictive stimuli and the reinforced cognitions and behaviors.
Keywords: Internet addiction, Video game, World of Warcraft, Reinforcement.
INTRODUCTION players get a game account and choose a specific server.
Each server contains thousands of players and is PvE (player
It has repeatedly been asserted that Internet addiction is a
vs environments: the players are fighting together against the
sub-category of addictive behaviors sharing the clinical and
non player characters), PvP (player vs player) or RP (role
neurobiological characteristics which can define addiction as
play, where players are supposed to chat and act as if they
a general clinical category. Thus, finding similarities
incarnate their character in the game) oriented. Servers are
between the examined new entity (Internet addiction) and
regrouped by languages.
those already established (e.g. nicotine addiction) may be a
momentous element to corroborate the claim. This paper will Players pick a character between two factions: horde or
review available data on certain features of Internet alliance. They choose a race (human, troll, gnome…) and an
applications which are supposed to act on the same ability (wizard, priest, warrior…). Everybody starts at level 1
neurobiological structures involved in substance-related with the same chance to progress through the game.
addictions, e.g. the mesolimbic dopaminergic system. Depending on their abilities, players will be assigned to one
of three specific roles: healing, making damages and tanking
In doing so, the focus will be on World of Warcraft
(absorbing damages). Until level 80 (the last level a player
(WoW), the most popular massive multiplayer online role
can reach with the last extension), the game is a succession
playing game (MMORPG) worldwide. At the end of 2008,
of repetitive quests based on a variation of: killing X
WoW was reaching 11 millions players. The last extension
monsters, bringing Y objects to character Z. The more the
of the game (Wrath of the Leech King) was sold at 2.8
player progresses in the levels, the more he will be able to
million copies within the first 24 hours of availability. join other players for group quests, group instances (specific
DESCRIPTION OF WORLD OF WARCRAFT dungeons for 5 players), raids (dungeons for 10 or 25
players) or player vs player fights such as arena tournaments.
Within WoW, players buy or download the game and get Before level 80, players cannot participate to arena
a number of free trial days, then they have to pay a monthly tournaments or specific raids. At any time players can join a
fee of approximately twenty US dollars (depending on the guild, i.e. a group with a structured hierarchy (guild leader,
country in which they bought the game). At the beginning, officers, members and rookies) designed to enhance
progression, share competences and, at level 80, to organize
specific groups for raids. The rapid progression in the game
*Address correspondence to this author at the Division of Addictology,
University Hospitals of Geneva, Rue Grand-Pré 7OC, 1202 Genève nor only depends on grouping with others in guilds, but
Switzerland; Tel: + 41 22 372 57 50; Fax: + 41 22 372 57 54; mainly on spending an amount of time playing the game.
E-mail: Gabriel.Thorens@hcuge.ch The more one plays, the faster he could reach top levels and
1874-9410/12 2012 Bentham OpenWhat is Addictive in Internet? The Open Addiction Journal, 2012, Volume 5 15
acquire interesting objects. This could be a facilitating factor The Products of Internet Addiction
to addictive way of playing; such as the attractive social
Some of the most important aspects of learning and
aspect of the game.
expression of motivated behaviors (and addiction in
DISTINGUISHING VECTORS AND PRODUCTS IN particular), have consistently been found to be related to a
THE FIELD OF ADDICTIONS network of cerebral components interconnected via
glutamatergic fibers, receiving dopaminergic afferents from
One neglected issues in the discussion of addictive
the ventral tegmental area (VTA) and comprising especially
products is the distinction between addictive products and
the prefrontal cortex (PFC), the hippocampus, the amygdala
their vectors. We hereafter will first try to clarify the
and the nucleus accumbens (NAcc) [1]. The activity of the
product-vector distinction through the example of nicotine
NAcc, a major part of the ventral striatum and a central node
addiction, and subsequently discuss it with regard to internet
within the limbic system, will be the main focus of the
addiction. present review. NAcc serves as an interface between
The distinction between addictive product and vector corticolimbic regions important for motivation and motor
becomes rapidly evident when examining the triad cigarette, regions important for behavioral output and plays a key role
tobacco and nicotine. Nicotine, the addictive substance, is a in generating motivated behaviors related to natural rewards
component of tobacco, which itself is most often consumed as well as drugs of abuse. It seems among others to mediate
as cigarette. Thus, the product nicotine is carried by tobacco, the reinforcing impact of drugs of abuse.
which therefore becomes a vector for nicotine. We could call
The ventral striatum/nucleus accumbens has been found
this a vector of first order regarding nicotine. A cigarette, on
to be activated in human neuroimaging experiments when a
the other hand, is a mean to carry tobacco. We will thus call
reward is received as well as when a reward is expected [2].
it a vector of second order regarding nicotine. This leads to
For example, ventral striatal activity correlates with the
multiple possible combinations between products and
amount of money a subject can earn in an experiment and
vectors. For example, consider that nicotine can be carried thus indicates reward value. The predictability of the reward
by tobacco, by patches, by gums, etc. Tobacco can be
seems to be the most important information the NAcc
smoked by means of cigarettes, cigars, pipes, water pipes,
carries. It has been proposed that it is not the prediction error
etc. A cigarette can contain tobacco, marijuana, etc.
but salience in general that is coded by the NAcc [3].
The addictive effects of smoking a cigarette will depend: Salience can be defined as the property of a stimulus that is
• On the addictive property of nicotine, i.e. from unexpected as well as arousing and elicits an attentional–
behavioral switch. This position is among others sustained
specific effects which will generate addiction (which
by evidence that negatively rated stimuli elicit activation in
is subject of pharmacodynamics).
the NAcc too.
• On the concentration of nicotine in tobacco, i.e. from
All known addictive drugs have been found to increase
properties of the vector of first order (which is subject
of pharmacokinetics). the extracellular concentration of dopamine in the nucleus
accumbens.
• On the design of cigarette, i.e. from properties of the
vector of second order (which again is subject of INTERNET STIMULI WHICH ACTIVATE THE
pharmacokinetics). STRIATUM
• On the individual vulnerability of the smoker (which We will hereafter review different classes of
is subject, in part, of pharmacogenetics). environmental stimuli which have been found to be
associated with activations of the ventral striatum, and try to
• On the technique of smoking. parallel them with specific features and contents of WoW.
The first 3 factors will be the topic of the present paper. Nucleus accumbens dopamine levels have not only been
The questions that arise are thus: found to be elevated in response to primary rewards such as
food delivery or sexual stimuli, but also in response to
• Which are the stimuli within the internet that may secondary rewards like monetary incentives [4-6].
possibly induce addiction related brain processes? We
will describe stimuli presented by Internet contents While there are no explicit references to sexual content in
which have been described in other contexts to induce WoW, players can chose between a male or female character
addiction related neurobiological activities. Thus, we and can customize their appearance. Choosing “sexy” outfits
will try to define the product of internet addiction. may therefore sexualize the content. The interaction between
players through vocal or written chats is a possible way of
• Which are the properties of Internet applications that seductive behavior. Some gamers overuse the in game
promote the addictive efficiency of the products? seduction and may gladly gender swap in order to benefit
Thus, we will try to examine the addiction promoting from some gamers generosity (offering some rare objects) or
properties of the first order vector, the WoW assistance. The anonymity may also contribute to enhance
software. such seductive social interactions. Furthermore, Internet is
• Which are the properties of the Internet technology most likely known to enhance the intensity of the
that boost the development of addictive Internet interpersonal interactions as described by Walthers [7] as
consumption behaviors? Thus, we will try to analyze “hyperpersonal communication”.
the addiction promoting properties of the second The presence of primary rewards is thus probably rather
order vector. limited. Secondary rewards are, on the other hand, frequent.16 The Open Addiction Journal, 2012, Volume 5 Thorens et al.
In an interesting PET-study, raclopride binding to dopamine Fairness is a central preoccupation for the designers and
receptors in the striatum was found to be significantly administrators of WoW. Thus, GMs (game masters, i.e.
reduced in 8 male volunteers during a video game which employees of the game editor who play a mediating role in
involved learning to navigate a tank for a monetary incentive game) are constantly accessible, answering questions and
[8]. resolving quarrels between players. As in “real world”
human society, specific rules have been edited, forbidding
Humans are living in a highly social environment, in
harassment, stealing, etc. transgressing these rules can lead
which most accomplishments happen through collaboration
to a definitive ban of a player account. Moreover, the WoW
with others [9]. Cues that indicate social acceptance or being
community constantly develops social regulations within the
treated fairly by others may thus be highly salient and
game. For example, a specific WoW term for thieves has
potentially induce reinforcement. Several neuroimaging
studies have actually reported activation in the striatum areas been coined: “Ninjas”, whose “bad behaviours” are
denounced in the general chat channel.
in response to several social stimuli [10].
Human social hierarchies are prominent in many
It has repeatedly been found that cooperative social
different settings (domestic, professional, recreational)
interactions do activate the striatum whereas non-cooperative
where they define implicit expectations and action
behaviors do not [2, 11]. Also, such activations have been
found when subjects experience mutual cooperation with a dispositions that drive suitable social behaviors [15]. Status
within a social hierarchy is often made explicit (e.g., via
human partner compared with mutual cooperation with a
uniforms, honorifics, verbal assignment, or even in some
computer partner, and this despite the fact that the monetary
languages via status-specific grammar), but it can also be
gain was identical in both situations [12].
inferred from cues such as facial features, height, gender,
Within WoW, the way players interact with other people age, and dress. According to Festinger’s theory of social
is very progressive. When starting, there is no need to play comparison processes [16], hierarchical ranks play a
with other human characters; players can progress on their significant role in achieving accurate self-knowledge and
own. They are, yet, always surrounded by others they can self-improvement. This is particularly so when subjects
compare to (there is an option in the game, for looking at make upward social comparisons, i.e., comparisons between
their experiences or equipments). It has, besides, been found oneself and an individual of higher status.
that during the leveling phases, players tend to progress
faster if they play alone [13]. In a recent study using an interactive game, two
experiments were used to create a social hierarchy [15].
Furthermore, even the “non collaborative” parts of the Brain activity in ventral striatum was significantly greater
game, i.e. the “player vs player competition”, are actually all when subjects viewed a player of a higher rank than a player
designed to integrate important collaborative elements. For of a lower rank. In another interesting study, Erk et al., [17]
example, the so-called “arena fights” are designed to let presented different types of grey-scaled photographs of cars
compete 2 vs 2, 3 vs 3 and 5 vs 5 players, but never 1 vs 1. (sport cars, middle-sized cars and small cars) to men. They
Players have to collaborate with at least one other person if were asked to assess the attractiveness of the cars
they want to engage in such “arena fights”. Also, it becomes irrespective of the costs or practical considerations. Sports
imperative for ambitious players to affiliate with cars were judged by the respondent’s significantly more and
complementary characters, to counterbalance their own small cars significantly less attractive than medium-sized
weaknesses. For example, a strong warrior will try to team cars. More attractive cars elicited stronger activations in
with a frail priest, a character that has the capacity to heal ventral striatum. It has been proposed that sports cars do
injuries of the other characters, who will reciprocally be able signal social dominance, as dominance and social rank are
to heal him. mediated by individual attributes signaling wealth and
Human studies have suggested that fairness based superfluity (the peacock’s tail principle).
cooperation may be even more reinforcing than cooperation Not only do social comparisons affect activation levels in
in itself. Fair offers e.g. lead to increased activity in the the ventral striatum, even if subjects are not actively engaged
ventral striatum compared with unfair proposals of equal in decision-making [18] but the acquisition of a good
monetary value [9]. In a particularly illustrating study [14] reputation was also found to activate the striatum [10].
subjects first played a sequential prisoners dilemma game
The more WoW users play; the more they need to
with (confederate) fair and unfair opponents. The focal
interact with others to progress, i.e. the more they have to
subjects were then scanned (using fMRI) when a slight pain
– an electrical shock – was administered either to themselves compare themselves with their opponents and teammates.
Thus, the development of tenaciously competitive guilds can
or to confederate partners who behaved fairly or unfairly.
regularly be observed, that are largely oriented in breaking
Both men and women exhibited empathic responses in
game records and being first in achieving specific game
anterior cingulate and anterior insula when the fair partner
goals. Their hiring criteria are very strict and their rules are
received pain. However, only men reported a higher desire
nearly martial. Players can access these guilds only if they
for revenge against unfair partners, and also exhibited
activation in the NAcc and orbital prefrontal cortex when are ready to play 3 to 5 nights per week and to keep a very
competitive level if they do not want to be excluded.
unfair partners were shocked. Male revenge desire ratings
across subjects were also correlated with the estimate of Also, the equipment of characters (armory, weapons etc.)
NAcc activity, consistent with the view that there is a reward is classed in different categories: common, rare and “epic”
value in observing the punishment of unfair partners. (the toughest to get). These equipment classes are rendered
easy to spot by other players, as they are marked by differentWhat is Addictive in Internet? The Open Addiction Journal, 2012, Volume 5 17
colors. For example, all “epic stuffs” are purple. The game a determined amount of time or after a determined number of
also includes a feature permitting with a simple command to correct responses. These conditions can always stay the same
check all equipments of each nearby player. (fixed) or can change over time (variable). Learned
behaviors are acquired more slowly with intermittent
Just as sports cars can signal social dominance by
signaling superfluity (the peacock’s tail principle), WoW reinforcement, but the response is more resistant to
extinction.
gives the possibility to acquire not only useful objects (in
term of improving abilities), but plenty of ostentatious There are four schedules of partial reinforcement, which
ornamental objects, e.g. a dragon who has the same speed as all differ regarding the elicited response patterns: Fixed-ratio
a normal mount but a much more showy aspect. schedules, variable-ratio schedules, fixed-interval schedules,
Furthermore, players can acquire “pets”, which are simply and variable-interval schedules. In WoW, we can find
“useless” animals following the avatars. Some of these particularly variable-ratio schedules and fixed-interval
“pets” are especially rare and difficult to acquire. schedules.
Finally, humor, another important social interaction Variable-ratio schedules occur when a response is
feature, has been found to engage the nucleus accumbens reinforced after an unpredictable number of responses. This
[19]. The degree of humor intensity was positively correlated schedule creates a high steady rate of responding. Gambling
with BOLD (Blood-oxygen-level dependent) signal and lottery games are good examples of variable ratio
intensity. schedules. Variable-ratio schedules are best for maintaining
behavior.
Amusingly, humor is largely present in WoW. E.g. there
are various “Easter eggs” integrated within quests, This type of schedule seems to be largely the basis of
environment, nonplayer characters, etc., to be found by WoW. Players are, e.g. requested do a repetitive rapid task
players. They are often humorous references to literature, (killing monsters) to get a potential reward which is always a
movies, etc. For example, the character called Haris Pilton certain amount of virtual money and sometimes a rare item.
sells the biggest and most expensive bag of the game. This item represents the reinforcer after an unpredictable
number of responses (0.5% chance to be obtained by killing
The First Order Vector a monster).
While the occurrence of salient stimuli during the game Fixed-interval schedules are those where the first
is a necessary causal factor for reinforcement, it is in itself response is rewarded only after a specified amount of time
not sufficient. The mode of presentation of these stimuli has elapsed. The time period required is always the same.
represents another important issue. The next step will be to
question characteristics of the first order vector (i.e. the This schedule causes high amounts of responses near the
WoW-software) which are suitable to sustain the reinforcing end of the interval, but much slower responses immediately
effects of the stimuli. While nicotine’s effect largely depends after the delivery of the reinforcer.
from its kinetics, the same can be supposed for WoW. Thus, WoW uses fixed-interval schedules too. For example,
the “kinetics” of the game can be expected to basically changing silver into gold is an ability of the profession
influence its addictive properties. “Kinetics” in this context “alchemists”. After having changed one silver ingot into a
means the pattern of stimulus-presentation. gold ingot, a fixed time interval begins during which no
The model of operant conditioning will be used to other conversions are possible. Another example of fixed-
examine this issue. Operant conditioning is the process of interval schedule applied in WoW is the one weekly
behavior modification in which the likelihood of a specific authorization to compete in specific rewarding instances.
behavior is increased or decreased through positive or Ratio schedules produce higher rates of responding than
negative reinforcement each time the behavior is exhibited. interval schedules, when the rates of reinforcement are
Through operant conditioning, an association is made otherwise similar. Variable schedules produce higher rates
between a behavior and its consequence. and greater resistance to extinction than most fixed
Hence the question arises: how is WoW designed in schedules. The variable-ratio schedule produces both the
order to use addictive stimuli in operant conditioning? highest rate of responding and the greatest resistance to
extinction. This also explains gamblers’ addictive behaviors
Stimuli may be presented in the environment according at slot machines, which are designed to apply variable-ratio
to two basic categories of schedule: continuous and schedules. The same is true for WoW.
intermittent.
COMPOUND SCHEDULES
In continuous reinforcement, the desired behavior is
reinforced every single time it occurs. Generally, this Thus WoW seems to use most of the simple reinforcing
schedule is best used during the initial stages of learning in schedules, it can also combine them to become so-called
order to create a strong association between behavior and compound schedules. These combine two or more different
response. Once the response is firmly attached, simple schedules in some way using the same reinforcer for
reinforcement in research is usually switched to a partial the same behavior.
reinforcement schedule. When analyzing WoW, it becomes
Multiple schedules are schedules where anyone of two, or
rapidly evident, that both classes of schedules are used in a
more, schedules may occur with a stimulus indicating which
compound manner, which will be discussed below.
one is in force. For example, a schedule A may be
In intermittent (or partial) reinforcement, the response is operational when given a red light and a schedule B when
reinforced only part of the time. The reward is delivered after given a yellow light. In WoW, such a change of schedule can18 The Open Addiction Journal, 2012, Volume 5 Thorens et al.
be found for example in the battle against specific monsters. The Second Order Vector
Some monsters can change their form, switching between
Just as cigarettes can be considered as vectors of second
two or more shapes and colors. Each form signals a different
order to carry tobacco and nicotine, the internet technology
schedule according to which it can be defeated. In one form,
represents a vector of second order to carry the WoW game.
the monster can be vulnerable to a certain amount of sword
hits (variable-ratio schedule), and in the alternative form The characteristics of second order vectors may be
considered regarding two aspects: (a) accessibility/facility of
only after a certain time lap (variable-interval schedule).
use, and (b) rapidity of action.
Concurrent schedules are those, where 2 or more
Regarding the accessibility/facility of use aspect,
schedules are simultaneously in force though not necessarily
commercially manufactured cigarettes today represent the
on 2 or more different response devices, and reinforcement
on those schedules is independent of each other. Thus, they best option to facilitate initiation and maintenance of
nicotine use. Similarly, Internet technologies have constantly
are schedules of reinforcement that are simultaneously
been developed in order to increase the so-called AAA
available to a subject, so that he can respond on either
principle (accessibility, affordability, and anonymity),
schedule. Each behavior pays off according to its own
rendering Internet products increasingly available for a large
schedule of reinforcement. Concurrent schedules often lead
population. An obvious interest for the game designers is to
to rapid alternation between the keys. One illustrative
example from WoW may be the possibility to defeat an implement WoW on mobile devices, improving the vector
for the same product. In doing so, the salient stimuli present
enemy through different weapons or magic spells, each
in Wow will remain the same, but the availability of the
method having its own schedule of reinforcement.
product will greatly increase. There is already a version of
Another form of compound schedules is the so called the WoW armory (an online list of avatar’s characteristics
chained schedules, where reinforcement occurs after two or and statistics) available on some new phones.
more successive schedules have been completed, with a
Regarding the rapidity of action aspect, the diffusion
stimulus indicating when one schedule has been completed
speed of addictive substances in the brain has been
and the next has started. Chaining thus involves linking
recognized as affecting their reinforcing effects. This
discrete behaviors together in a series, such that each result
association has among others been shown in PET studies that
of each behavior is both the reinforcement (and
evaluated the pharmacokinetics of cocaine, documenting that
consequence) for the previous behavior, and the
discriminative stimuli (or antecedent) for the next behavior. it was the fast uptake of the drug into the brain but not the
brain concentration per se that was associated with getting
At the end of the chain, a reinforcer is given. This principle
high (reviewed in [20]). Thus, faster the dopamine increases,
is largely present in WoW. For example, quests are usually
the more intense the reinforcing effects. Speed is also an
chained to attain a specific goal. E.g. the avatar of a player is
imperative preoccupation for the game designers: not only
solicited to acquire a specific metal (obtaining experience
have the ingame speeded (i.e. how fast your avatar is
points and possibly gold), to carry it to a blacksmith (gaining
again rewards), to use the sword manufactured by the moving) but also the fluidity of the game, that depends
notably on the data transfer technology. Massive efforts are
blacksmith to combat a monster (gaining rewards), and
done by the designers to prevent lags or delays in the game.
finally to bring the monster’s head to the king (receiving a
Thus, the time correlation between potentially addictive
particularly valuable item). A further striking example is the
stimuli and the reinforced cognitions and behaviors has been
leveling process itself.
improved.
A further interesting form of reinforcement which has
been described is the so called differential reinforcement of CONCLUSIONS
high rates (DRH). This term describes a schedule of The aim of the present paper was to discuss similarities
reinforcement in which the reinforcement is provided at the between Internet addiction and already established
end of a predetermined interval contingent on the number of addictions. We have taken WoW as an illustration,
responses emitted during the interval being greater than a comparing it notably with nicotine. It appears that various
gradually increasing criterion based on the individual's environmental stimuli which have been found to be
performance in precious intervals. DRH can be used to associated with activations of the ventral striatum, are
increase high rates of responding. It is like an interval recurrently presented during the game, and may act as
schedule, except that a minimum number of responses are behavioral reinforcers leading eventually to addiction.
required in the interval in order to receive reinforcement.
One remarkable example from WoW may be the healing Regarding the first order vector aspects, it appears that
activity of healers. Take for example, a healer who is the game regularly presents the salient stimuli in patterns
committed to restore health points of a warrior who himself corresponding to operant conditioning, using compound
is fighting a monster. As the warrior may continuously be schedules optimizing on one hand the acquisition of the
injured by the monster, he has to repeatedly be healed by the reinforced behavior, and on the other hand, its maintenance
healer in order to continue his fight interval condition. It will and its resistance to extinction.
be the healers’ (and the warriors’) interest that the healer Finally, the addictive properties of WoW have probably
rapidly and repeatedly casts the healing spells, as they “cool been facilitated by the last technological developments,
down” within few seconds, i.e. loose their effect. It is also rendering the game more accessible, and permitting very
prohibited to automatize these procedures, thus forcing the strong time correlations between potentially addictive stimuli
healer to repeat the action manually. and the reinforced cognitions and behaviors.What is Addictive in Internet? The Open Addiction Journal, 2012, Volume 5 19
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Received: October 4, 2011 Revised: October 4, 2011 Accepted: January 19, 2012
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